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The Cancer Cats Get In Their Mouth

Squamous Cell Carcinoma In Cat's Mouths

I really couldn’t come up with a catchy title. It’s a sucky disease. Cancer sucks. So the title sucks. It’s a theme.

But let’s talk about Squamous Cell Carcinoma. It’s a type of cancer that can occur in a variety of places. Humans get it on their skin (reason to wear your sunblock!!). Dogs and cats can get this kind of cancer on their skin as well, but it is not very common, because they have fur for sunblock! Because the skin version is related to UV exposure (like our version) it tends to affect more light colored animals, and in areas with thin fur, like the nose, tips of ears, etc.

We’re talking about a different version of Squamous Cell Carcinoma. A much deadlier, suckier one.

This is the most common oral tumor of cats. If you find a cat with a mass growing anywhere in the mouth (lips, gums, palate, etc) we assume it is a squamous cell carcinoma until proven otherwise. If we wanted to 100% confirm it was this cancer, a biopsy of the growth under general anesthesia is the best way. Some vets will try to cut back the tumor (debulking) while they are at it, but this does not really improve the prognosis. This cancer does not tend to metastasize, or spread throughout the body, which is a good thing. So why do we hate it so much?

The tumor grows in the mouth and can invade the bones of the skull. We use the term “locally invasive” to indicate it does not spread throughout the body, but really can get out of hand in the area it is in. We hate this disease because it makes us euthanize a cat who is otherwise healthy. From the neck down, the cat is healthy and normal! But this awful tumor invades the mouth, preventing the cat from eating. We obviously don’t want the cat to starve to death, so humane euthanasia is eventually chosen as opposed to starvation.

In some lucky cats, the tumor grows on the bottom jaw, which we can surgically remove (yes, cats can live with a partial bottom jaw!). This is often best performed by a specialist, as it is a very involved procedure. When the tumor invades the upper jaw (the maxilla) that connects to the face, it can even effect the eye! Obviously, we can’t surgically remove half your cat’s face. I have had some owners pursue radiation therapy for these cats. Unfortunately, the eye is usually in the field of radiation, and may suffer because of it. But some of these tumors do shrink a little.

What about a feeding tube? If the whole cat is healthy, and it just can’t eat, can’t we do it for them? I have had a couple clients who could not let the cat go, and we did a feeding tube. It does not help significantly improve the quality of life of these cats. The tumor continues to grow, eating away at the skull. We have teeth falling out because the bone that holds them in is so abnormal. We have a cat drooling blood all the time, and they are generally very uncomfortable.

The most common symptom we see with oral squamous cell carcinoma is the breath. I often joke I can diagnose this disease simply by walking in the room. It is a smell like no other – a smell of rotting, decaying tissue. Sometimes the swelling in the face is apparent from across the room, while other times we have to open the mouth to look.

This disease sneaks up on people…how often do YOU look in your cat’s mouth? And if you are not keeping up on your cats dental care, you may just think it’s a bad tooth you’re smelling. Bloody drool is another common symptom, but again, people often blame dental disease (which the cat very well may have as well!).

So if you notice your cat’s breath smelling extra bad, get him to the vet! If caught early, and if they happen to grow in the right place, some of these tumors may be resectable. Otherwise, knowing what you are dealing with lets you focus on making your cats remaining weeks/months as good as possible.

Web-DVM guest blogger Dr. Karen Louis is a practicing small animal veterinarian.  See more of her articles at her blog at

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